It is generally known that vehicle wiring harnesses are very complex and cumbersome to modify. The wiring harness design and development process begins with development of individual components (e.g., control devices, sensors, actuators, connectors, accessories, etc.), followed by the development of a system circuit plan and a wiring plan.
At that point, a new or modified vehicle harness is ready to be represented in a three-dimensional geometry. This three-dimensional geometry is important for defining the installation space for the various components and the wire harness, for selecting and positioning suitable mounting elements (shafts, grommets, clips, etc.) and for defining the bundle lengths for later conversion into a two-dimensional drawing.
The three-dimensional geometry may be generated using commercially available modeling software, such as CATIA V5, in the form of a wire harness box (WHB) package. The WHB package refers to the virtual, geometric three-dimensional depiction of all wire bundles and components that comprise a particular vehicle wire harness.
One of the uses of the three-dimensional WHB package is the generation of a two-dimensional computer aided design (CAD) drawing, which encompasses all geometrically-relevant components (e.g., connector housing, ring terminals (eyelets), connectors, accessories, mounting parts, wiring protection, and accessory parts; referencing is generally done via a occurrence ID and part number), as well as length tolerances, geometric variances, and much more. Much of the actual design, engineering, pre-production, and bills of material are all completed using such a separate two-dimensional drawing, as opposed to the more cumbersome three-dimensional model.
While the content for the two-dimensional drawing is largely derived from the three-dimensional WHB package, it must generally be supplemented with additional information (e.g. connectors, routing points, parameters about the type of winding to be performed, production notes, length tolerances, etc.) which is lost during the conversion process. As such, the generation of the two-dimensional drawing is labor intensive, being manually created from the aforementioned three-dimensional WHB package. For example, cable lengths and positioning points from mounting parts (e.g., clips, holders, grommets, shafts) must be measured in the three-dimensional model and manually transferred to the two-dimensional model.
Other manual additions that the developer/wire harness designer must make to the two-dimensional drawing vs. the three-dimensional model include specified bundle lengths, minimum lengths in dimensional chains and length tolerances, rough drawing of the connections, orientation of mounting parts (sectional views), location of connectors (splices), winding types (incl. cross-winding and bindings), etc.
Beyond the above, one of the most labor intensive steps to wires harness design is the need to disentangle (or unwind) the two-dimensional drawing in order for it to be usable in connection with the aforementioned design, engineering and pre-production processes, as well as template for the formboard drawing, which is needed or manufacturing. This additional manual step is required because available CAD tools are able to generate the two-dimensional drawing from the three-dimensional model by setting one coordinate (usually the Z-coordinate, possibly the y coordinate mainly in the case of door wiring harnesses) to “0,” thus causing the cable to fall into the resulting plane in a manner similar to a projection. The net effect of this, as shown in FIG. 1, is that the information about the outgoing direction of the bundles at the nodes is lost. Thus, in the resulting two-dimensional plane, the bundles, which typically lie one above another in the actual physical implementation, are required to be unwound or disentangled by the designer for the drawing to be further usable, as noted above. This involves having to manually stretch and orient the two-dimensional bundles, which is a laborious process.
As such, there is a need in the art for an improved approach for eliminating the need to minimize the labor required to unwind or disentangle two-dimensional wiring harness drawings which are based on three-dimensional wire harness models.